Substance abuse treatment outcome studies typically rely on follow-up assessments of clients to evaluate the effects of clinical interventions. In many instances, subjects are given cash or cash-equivalent vouchers to compensate them for their time and effort in completing the research measures. Ethical objections are commonly raised, however, to giving subjects substantial sums of cash for their research participation because this might precipitate relapse to substance use or might unduly influence subjects to participate in the protocol. Very few studies, however, have empirically investigated the actual effects on subjects of different incentive arrangements. Investigators and IRB members often must rely on anecdotal accounts or their own preconceived notions about the possible effects of different payments arrangements when engaging in an ethical risk/benefit analysis. The proposed study will involve a 2x3, randomized, parametric analysis of different modes (cash vs. gift certificates) and magnitudes ($10.00 vs. $40.00 vs. $70.00) of remuneration to subjects for completing a research follow-up assessment. All other aspects of the follow-up protocol (e.g., degree of staff-to-patient interaction, reminder letters and phone calls, transportation assistance) will be carefully monitored and held constant across all payment conditions. Subjects will compete an Addiction Severity Index (ASI; McLellan, Luborsky, O'Brien, & Woody, 1980; McLellan, Metzger, & Kushner, 1991; McLellan, et al., 1992) at admission and will be scheduled to complete a follow-up research assessment at 6 months post-admission to treatment. The follow-up battery will include an ASI, as well as several other instruments designed to assess subjects' perceptions of coercion, satisfaction, benefits, harms, and inconveniences associated with being in the research study. At the 6-month follow-up, subjects will subsequently be asked to come in again 3 days later to complete a brief, post-follow-up satisfaction survey, and to provide an additional urine specimen. This will be the first randomized, controlled effort to systematically examine specific parameters of subject remuneration, and to empirically evaluate the risks and benefits associated with different incentive arrangements. The results will assist researchers and IRB's in their task of developing and implementing effective, validated, and ethical follow-up procedures.